1982 xj750 maxim starting idling issue

Was having some trouble getting it started . Then finally was able to get it running and it will not run with the choke off . Choke has to be at 1/4 to stay running . When I throttle it up it will take off and rev all the way up to 3000-4000 . The only way to get it to rev down is turn the choke down and will run at about 1000-1500 and not stall . It sit since last winter . I did put fuel treatment in the gas . I changed the plugs and air filter and have changed the oil and filter . I am looking at having to clean the carbs? Or could it be a carb adjustment ? Any local people in the Lansing area work on bikes that could go through it for me and possibly diagnose . I will pay of course. Looking for something cheaper than a bike shop though . Any help would be awesome .

 

Also the carb rubber boots looked cracked , could they be cracked and have leaks .

 

Sounds like you haven't or do not know if the carbs have been cleaned/ rebuilt.... chances are really good they need to be cleaned/ rebuilt (you need to replace some of the 30+ year old rubber parts and gaskets).

There is a legend of a Fitz a Big one at that, he resides somewhere in the mitten. Sadly he is wrapped up in doing other things and hasn't been heard from in awhile. There may be other members in Michigan that can help - where in the state are you?

On a scale of 1 to 5 how would you rate your mechanical ability? Rebuilding carbs isn't very difficult, patience, pictures and attention to detail is all you need.

Side note: Did you replace the air filter with an OEM one or something fancy and different?

 

I'm probably a 4-5 when it comes to cars and trucks. I do all my own mechanic work . I work on my own tractors as well. This is my first motorcycle so I haven't done much as far as bikes . I haven't done the carbs but the person I bought it from said they did . But considering some of the fixes and some of the mods they made on the bike I wouldn't think it was done properly . I'm just afraid of messing something up or losing a part and not knowing what's wrong . Only carb work I've done was on a lawn mower engine . air filter I got on amazon nothing fancy just the cheapest one they had . I guess I'll just plan on doing the carbs . Is there a specific rebuild kit I should get ?

 

Also what should the running temp , I put a infrared thermometer on it and was around 230-250. And the exhaust pipes were over 350. Although two of the header pipes were over 350 and the other two were 150 . Might be a stupid question but is that normal ?

 

Not sure if you will need a whole kit, but plan on at the minimum getting throttle shafts seals, idle mixture screw o-rings and their washers, the o-rings for all the fuel rails, and new butterfly screws, a gallon can of carb dip with a basket in it, and 8 cans of cheap aerosol carb cleaner.....the link in the upper right corner will get you all the info and parts you will need

 

Ok thank you , i really appreciate it . Also I went out and did a plug test and pulled the plug wires off to see if it ran any different. #2 and #4 did nothing when I pulled them off. I grounded the plug and was getting spark . Maybe it was too weak . Plugs are new . Or does that mean 2 and 4 carb are the problem ?

 

the pipes should be close to same temp. sounds like your pilot jet circuits are clogged thats what runs the bike at lower rpms.
pilot jet circuit is pilot jet pilot air jet and mixture screw. there are tiny holes in the top of carb throat on the butterfly side. that is where the fuel comes in

 

some interesting reading for you

THE SECRET LIFE OF CARBURETORS

Something New, Something Naked

TALKIN' TECH: Various thoughts on various issues

 

And there is this:
http://xjbikes.com/forums/threads/in-the-church-of-clean.14692/
You skill level is more than enough to get you through a carb rack. They are finicky and unforgiving if not assembled and tuned proper. But you can do it!

What kind of tractor(s) do you have? My 'other' ride is a Leyland 270.

 

Ok so I got the rack off and opened one up and noticed that there wasn’t a plate inside the carb where the air jet screws are ( I think that’s what they at called )the Manual shows a plate . Here’s a pic , my question is is the plate missing . Also while taking them a lot of the screws were loose and the boots weren’t tightened down very well . And by loose I mean I could turn them with my hand. So I’m assuming the carbs were poorly done .

 

not needed the plate in the carbs just an extra part

loose screws and clamps, missing parts POsyndrome

 

Time to check every bolt and nut on the bike? If you can't trust PO with your carbs, would you trust them with your life?

 

As soon and I get it running properly it’s going to a shop to get everything checked. I have a local shop that I trust . Thanks for the help guys I think I have a idea what needs to be done . Just have to order the parts and start cleaning

 

careful... get those carbs sorted out and then we should talk some more.

 

Do not take your bike to a shop.....
.they will just take your money......

You can do whatever is required with the help from this forum

 

Anyone ever look into the throttle shafts seals from other bikes . Read on a forum someone used a Suzuki brand part that was the same seal and they were only 1.89 a piece ....here’s the link
http://www.partzilla.com/parts/detail/suzuki/SP-13651-51010.html. The guy said they were for a hitachi carb . Anyone have measurements or a pic of what the seal looks like ?

 

I would think that mikuni and hatachi are the ones who determined what parts fit the carbs they make not yamaha.
that is what the seals look like. a #11 oring (x2 each side) can be used as replacments for hatachi carbs.

 

Do you know the size of the fuel rail o rings , and the mixture screw o ring ?

 

Take the guess work out of it.
Click on the XJ4Ever link in the upper right hand corner, start a conversation with member Chacal. Order your parts from him.

Or - order from any of the scads of other 'vendors' out on the WWW. Bemoan the poor customer service, the lack of attention to detail with ensuring you have all of the right parts for what you are trying to accomplish on your specific bike and then bitch about how long it takes to get the parts delivered (even though you have to send half back cause they are wrong - and the other half wasn't even delivered - so now double your delivery time)... Your choice.

I made the mistake once of ordering from an actual Yamaha dealer on the WWW; waited and waited, tried to contact them to find out where my order was - no reply, called them , got some run around confused AF answer from them that they aren't sure where the order is..... I did save a couple bucks - gained more gray hair, kicked my blood pressure up a notch and lost 3 weeks of riding time.

Do what you want, but you have been advised.... just sayin'

 

Harbor Freight sells a metric nitrile o ring kit that had the correct ones in it to fit the fuel rails for like 8 bucks, but it did not go small enough for the idle o ring.

 

Stump ....+1 on your answer

 

no I do not but the mix screw oring is very very small i get them from xj4ever as well as the fuel rail orings because wrong size could lead to fuel leaks and fire

 

HF just put in a new store about an hour away from me 3 gallons of gas and 2 hours of my time makes it worth going to xj4ever

 

ok I’ll order through xj4ever . I appreciate the help everyone . Knowing the parts will work is better than Saving a little cash ... this website has helped me greatly. Thanks for the help everyone